This invention relates to an automatic sewing machine, and in particular to the operation control thereof.
With the rapid progress of electronics technology in recent years, operations in a sewing machine such as sewing operation, speed control operation of a drive motor (electric motor), etc., have become to be placed under detailed processing control employing electronic controlling circuits, which has enabled a sewing machine to carry out many complicated operations and to have many improved functions. An enumeration of the functions newly developed includes: a function of arresting the needle at an upper position above the bed, a function of shifting the needle to a lower position for arresting the same there, a function of stopping the electric motor, in case of an emergency, by means of pressing a button other than the main button for the ordinary starting and stopping the electric motor, and a function of effectively selecting a desired stitch pattern from among a lot of stitch patterns by utilizing as few selecting buttons as possible, etc. Because these functions must be realized by the operator, by means of handling an operable means corresponding to each related function, so that the number of operable means is inevitably increased accompanied by the increasing number of the functions. Those operable means have to be usually arranged on a handy place for the operator, that is to say, on the front side of the machine facing to him or her, and this place is generally a limited and rather small one, being already occupied by the main button for the electric motor, a display panel for indicating a plurality of stitch patterns, selecting buttons for selecting a stitch pattern, etc., leaving little space to be spared. Arranging many kinds of operable means on the limited front side space detracts from the appearance of a sewing machine and likely to degrade the easiness of the operation (operability) of the machine. Each of the operable means has to be connected to an electronic controlling circuit respectively for being checked of its operation state, resulting in increase of the number of connecting lines, which naturally invites difficulty of wiring and sometimes mis-connecting of electric wiring. The reliability of sewing machines have been lowered by those troublesome problems.